1. Field of the Invention
The present invention relates to a hinge structure for use in joining a temple and a front rim in eyeglasses, particularly for use in an attractively slim front-and-temple combination.
2. Related Arts
Referring to FIGS. 5a and 5b, a conventional hinge structure for eyeglasses has two semicolon-like rotary metal pieces "a" and "b" interleaved and rotatably joined together by a pivot screw "c". One of the semicolon-like rotary metal pieces "a" has parallel circular extensions "k" integrally connected to its triangular block, leaving a circular space therebetween. The other semicolon-like rotary metal piece "b" has a cantilever-like circular extension "i" integrally connected to its triangular block, and the cantilever-like circular extension "i" can be fitted in the circular space of the semicolon-like rotary metal piece "a". Each circular extension has a through hole made therein.
One of rotary metal pieces can be soldered at its flat bottom "d" to the side joint piece (not shown) of the front whereas the other rotary metal piece can be soldered to the temple (not shown). Thus, the temple can be folded toward the front of the frame.
After being used for a long period such hinge structure is apt to get loosened because of frictional wear in the confronting surfaces of the rotary metal pieces. Also, the pivot screw is apt to be loosened, and accordingly the hinge is loosened. In any event the eyeglasses are not stable on one's face. When loosened, the pivot screw must be tightened. In the hope of preventing the frictional wear of the confronting surfaces of the rotary metal pieces "a" and "b" washers "e" are used, as seen from FIG. 6.
Referring to FIGS. 7a and 7b, the washer "e" comprises an eyelet disk "f" having an annular collar "g" integrally connected thereto. A screw "c" can be inserted in the center hole "h" of the washer "e". Referring to FIG. 6, washers "e" are laid between the confronting surfaces of the interleaved circular extensions "i" and "k" of the rotary metal pieces "a" and "b". Specifically the annular collar "g" of rotary metal piece "i" with its eyelet disk "f" sandwiched between the confronting surfaces of the interleaved circular extensions "i" and "k" of the joined rotary metal pieces "a" and "b", thus preventing the confronting surfaces from being worn.
As seen from FIG. 6, the cantilever-like circular extension "i" of the semicolon-like rotary metal piece is inserted in the circular space between the parallel circular extensions "k" of the counter semicolon-like rotary metal piece. This interdigitation prevents flat washers from being held between the confronting surfaces of the circular extensions of the opposite rotary metal pieces, requiring use of collared washers such as shown in FIGS. 7a and 7b. Use of such collared washers necessitates the enlarging of the through hole "j" of each circular extension, and accordingly the circular extension need to be increased in diameter because otherwise, the rotary piece cannot have a required strength.
As a recent tendency a very thin wire is used in making the frame of eyeglasses. The conventional hinge structure of FIGS. 5a and 5b, if used in joining the temple to the front rim, would appear above the thin wire temple on its upper and lower sides because the height H of the hinge structure is higher than the vertical size of the thin wire. The conventional hinge structure has an increasing width because of use of collared washers, and therefore, it projects outward from the temple-to-front joint unpleasantly. As a result the appearance of eyeglasses is less attractive.
Also disadvantageously, the number of manufacturing steps required in producing collared washers is larger than that in producing flat washers. In hinging the temple to the front rim of the frame, first, two small-sized collared washers are fitted in the through hole of the cantilever-like circular extension of one rotary piece, and then, the cantilever-like circular extension having the collared washers fitted in its through hole is inserted in the circular space between the parallel circular extensions of the other rotary part. These require time-consuming, tedious work.
One object of the present invention is to provide a hinge structure which is so small that it may fit the attractive slim frame of eyeglasses well, and can be easily assembled.